Worms to take care of city’s sludge
Wastewater sludge from Hamilton’s 145,000 residents will no longer end up in landfill.
Hamilton City Council’s finance and monitoring committee has given gave the green light to a new vermicomposting proposal, which will see more than 12,000 tonnes of sludge diverted away from landfill each year.
Instead of being transported to landfill at Hampton Downs, the new method will see the city’s wastewater sludge sent to a vermicomposting operation at Tokoroa where it will be mixed with paper pulp and laid in rows to break down and compost. Worms introduced to the rows will help break down the organic content, with the whole process taking around a year to complete. The end product, known as vermicast, can then be sold to farmers and forestry nurseries as fertiliser or soil conditioner.
The finance and monitoring committee endorsed the concept, giving its approval to award a contract to vermicomposting service provider NOKE for the disposal and beneficial reuse of the wastewater sludge.
The contract will be for a three-year period starting February 1, 2013, with a three-year right of renewal at the council’s discretion.
NOKE is the only largescale vermicomposting service provider in the central North Island, operating two leased sites at Kawerau (where wastewater sludge from Rotorua District Council and Western Bay of Plenty District is currently processed) and Tokoroa.
The NOKE operations are fully consented and compliant, and produce an ‘‘Aa’’ graded compost for beneficial reuse. The committee also approved the amendment of the council’s existing transportation contract with Transpacific Industries Group New Zealand to have the sludge transported to the Tokoroa site.
Councillor Daphne Bell, chairwoman of the council’s Sustainability Working Group which has been involved in discussions about the vermicomposting option, praised the initiative.
‘‘It is much better than our current process. This is definitely a move in the right direction which is in line with the vision of council’s Waste Management and Minimisation Plan and draft Sustainability Strategy. It shows council is serious about making good use of waste material.’’
The vision of the Waste Management and Minimisation Plan is for Hamilton to become recognised as a national leader in the minimisation of waste and ensure innovative and sound waste management practices underpin the city’s environmental, social, economic and cultural wellbeing.